150 



Another improvement is, instead of two fluted roller*, 

 to have one of them plain, but cliipt cross-ways, about 

 half an inch deep in various places. This prevents the 

 straw from rolling around the other fluted roller ; in 

 which case the straw must be immediately cut, otherwise 

 much mischief may be done. This is supposed to be a 

 Scotch invention, for it was introduced into Northum- 

 berland only in the year 1807. When chipped, the straw 

 adheres to the roller, without lapping round it, which it 

 is apt to do, when fluted, if the straw is damp. 



When horses are yoked in threshing-mills, they ought 

 either to have goggles, or to be blinded, as they are so 

 apt to look back. A.11 horses should have breechings to 

 <nable them to stop the machine, and many have been 

 VHed, and much mischief done, owing to the want of 

 so essential an article. The lever ought always to be 

 placed above the horse's back. 



Great diversity of opinion is entertained regarding the 

 kind of threshing-mill that is easiest wrought, some con- 

 tending for two movements, some for three, and others 

 for four. Mr Rennie of Fantasie recommends a mode 

 of trial which he thinks would set that matter to rest, 

 that of having three or four models of different move- 

 ments, but of equal power, to be constructed by an able 

 mechanic, and these to be wrought by means of weights, 

 which he thinks would at once ascertain which of them 

 had the easiest draught ; at the same time, it would be 

 difficult to say, with any degree of correctness, which 

 ought to be preferred. So much depends on a variety of 

 circumstances; as, i. The strength, quality and condi- 

 tion of the horses ; 2. The length and stiffness of the 

 straw ; 3. The ripeness of the grain i. 4. Its being well or 

 ill filled i 5. Its being dry or damp ; 6. The experience 



